Tag: Legionella Mitigation

News headlines about Legionnaires’ disease outbreaks are a stark reminder of a critical public health challenge that often originates within the very water systems of our commercial, institutional, and residential buildings.

Legionnaires’ disease, a severe form of pneumonia, is caused by Legionella bacteria, which thrive in specific conditions found in complex plumbing systems.

When cold water flow is minimal or stopped altogether, disinfectant levels evaporate, and temperatures gradually rise to the Legionella growth range (77–113°F, 25–42°C), leading to bacterial colonization and uneven free chlorine distribution throughout the system.

Understanding how these bacteria flourish in various parts of a building’s water infrastructure and how to prevent their growth proactively is crucial for safeguarding public health and ensuring compliance.

Understanding the Threat of Legionnaires’ Disease

Legionnaires’ disease is a severe lung infection contracted by inhaling small droplets of water (aerosols) contaminated with Legionella bacteria. Various building water systems, including showers and faucets, can generate these aerosols. It’s important to note that Legionnaires’ disease is not spread person-to-person.

Symptoms can range from mild to severe, including cough, shortness of breath, high fever, muscle aches, and headaches. While some individuals recover, Legionnaires’ disease can be fatal, particularly for those with weakened immune systems or chronic lung conditions. The severity and public impact of outbreaks underscore the critical need for effective and proactive prevention strategies.

The Critical Role of Balanced Recirculation

Recirculating cold water eliminates stagnation, which promotes harmful bacteria growth, and provides consistent distribution of residual chlorine throughout domestic cold-water systems:

• Keeps water moving
• Maintains water quality to reduce stagnation
• Ensures residual chlorine is distributed throughout the cold-water system
• Keeps water temperature in branches and risers evenly distributed, minimizing heat gain

How Thermostatic Technology Changes the Game

Implementing effective recirculation, particularly in large and complex plumbing systems, requires precision to ensure adequate flow to all branches without creating significant water waste or manual balancing. This is where self-actuating thermostatic valve technology comes into play.

How the CircuitSolver^® CSU-CW Valve Works

The CircuitSolver^® Union Cold Water valve, using innovative automatic thermal balancing technology, offers a robust solution for optimizing cold water recirculation loops, ensuring optimal conditions for Legionella control.

The CSU-CW valve utilizes the same reliable and precise thermal actuator technology as the original CircuitSolver^®. It addresses critical issues related to Legionella mitigation in cold water recirculation systems by maintaining a stable temperature. It accomplishes this by continuously monitoring the water temperature and modulating flow to maintain a set temperature at the end of each branch or riser.

The valve operates over a 10°F temperature range. For example, a valve specified for a desired return temperature of 60°F will open at 70°F (10°F above the desired return temperature). At 60°F, the valve is in its closed position. A bypass in the design always allows water to flow back to the pump so that the pump is never dead-headed.

The CircuitSolver^® Difference

Simplified Design & Operation

Unlike manual balancing valves that require extensive, often inexact, commissioning and re-balancing, automatic valves like CircuitSolver^® provide continuous, dynamic balancing. This eliminates the need for manual adjustments, saving time and labor while ensuring optimal, ongoing system performance.

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By intelligently directing flow only where needed, CircuitSolver^® thermostatic balancing valves maximize the effectiveness of the recirculation system, leading to both safety and cost savings.

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By taking a proactive, comprehensive approach to Legionella control and utilizing advanced technology like CircuitSolver’s automatic thermal balancing valves, you can transform your building’s water system from a potential risk into a safe, reliable, and compliant resource, mitigating Legionella bacteria.

Find more information about our thermostatic balancing valves here.

A Practical Guide to Legionella Control in Water Systems

Since its discovery in the summer of 1976, Legionella bacteria has been an ever increasingly hot topic in the plumbing industry, seeming to lurk in pipes and water systems, waiting to strike in a moment of lapsed attention or vigilance.

According to Smithsonian Magazine, the CDC reports that as of 2018, cases of Legionnaires’ Disease, pneumonia caused by aspirating the Legionella bacteria, have risen significantly. With nearly 10,000 cases reported in 2018 alone, Legionnaires seems to be running rampant in modern water systems.

While some attribute the sharp rise in case numbers to improved reporting, awareness, and testing methods, it has also been suggested that aging infrastructure and climate change could be contributing factors.

Foundational Strategies for Legionella Mitigation

While prevalent in modern plumbing systems, Legionella bacteria only presents a risk when able to colonize, typically in stretches of piping with warm, stagnant water. For many buildings, simple changes to system design and management procedures can significantly reduce the prevalence of Legionella bacteria and inhibit growth before it can begin.

1. Avoid “Dead Legs” in Piping Design
Minimizing the distance between supply lines and fixtures in your system design can reduce areas of stagnation in the hot water piping which could accumulate scale and biofilm buildup, a prime location for Legionella bacteria to set up shop.

2. Maintain Water Temperature Control
Legionella bacteria flourishes in warm water with comfortable temperatures ranging from around 70°F to 115°F. Storing water at temperatures above 120°F will generally help prevent colonization.

To prevent bacteria growth, specify hot water tanks that store water above 140°F (60°C) and use a mixing valve to recirculate it to the fixtures at 120°F (48.9°C) to comply with anti-scalding regulations.

3. Ensure Constant Recirculation
Keeping your recirculation pumps running at all times will keep water flowing and prevent bacteria from grouping together and adhering to pipe walls.

4. Perform Routine Maintenance of Equipment
The CDC recommends cleaning water tanks routinely including periodically draining the system to remove scale and sediment. This will prevent biofilm, organic debris, and corrosion from contaminating your water system.

CircuitSolver Sanitary Flush Valve

For domestic hot water systems using a heat-and-flush thermal disinfection method to prevent Legionella bacteria growth, balancing during the flush is essential to ensure thorough sanitation.

CircuitSolver Sanitary Flush Valve utilizes two thermal actuators for automatic thermal balancing of the system; one for normal DHWS operation, and the other for thermal disinfection. Click here to see how it works.